The following invention relates to a printhead assembly having printhead modules in a channel.
More particularly, though not exclusively, the invention relates to a printhead assembly for an A4 pagewidth drop on demand printer capable of printing up to 1600 dpi photographic quality at up to 160 pages per minute.
The overall design of a printer in which the assembly can be utilized revolves around the use of replaceable printhead modules in an array approximately 8½ inches (21 cm) long. An advantage of such a system is the ability to easily remove and replace any defective modules in a printhead array. This would eliminate having to scrap an entire printhead if only one chip is defective.
A printhead module in such a printer can be comprised of a “Memjet” chip, being a chip having mounted thereon a vast number of thermo-actuators in micro-mechanics and micro-electromechanical systems (MEMS). Such actuators might be those as disclosed in U.S. Pat. No. 6,044,646 to the present applicant, however, might be other MEMS print chips.
In a typical embodiment, eleven “Memjet” tiles can butt together in a metal channel to form a complete 8½ inch printhead assembly. 
The printhead might typically have six ink chambers and be capable of printing four color process (CMYK) as well as infra-red ink and fixative. An air pump would supply filtered air though a seventh chamber to the printhead, which could be used to keep foreign particles away from its ink nozzles.
Each printhead module receives ink via an elastomeric extrusion that transfers the ink. Typically, the printhead assembly is suitable for printing A4 paper without the need for scanning movement of the printhead across the paper width.
The printheads themselves are modular, so printhead arrays can be configured to form printheads of arbitrary width.
Additionally, a second printhead assembly can be mounted on the opposite side of a paper feed path to enable double-sided high speed printing.